This guy does a good job of explaining it.
My experience with a bad microphonic 6922 tube was as he described with a little ringing sound thrown into the mix.
Tap on top of your preamp lightly with two extended fingers. If you can hear your tapping through a speaker/s you have an excessive microphonic tube/s.
My experience with a bad microphonic 6922 tube was as he described with a little ringing sound thrown into the mix.
Tap on top of your preamp lightly with two extended fingers. If you can hear your tapping through a speaker/s you have an excessive microphonic tube/s.